Heating a moving conductor by electromagnetic wave irradiation in the microwave region



June 24, 1969 'M. 1.. LEVINSON 3,452,176

HEATING A MQVING CONDUCTOR BY ELECTRbMAGNETIC WAVE IRRADIATION IN THE MICROWAVE REGION Filed May 24, 1967 HEATING A MOVIN G CONDUCTOR BY ELEC TROMAGNETIC WAVE IRRADIATION IN THE MICROWAVE REGION Melvin L. Levinson, 1 Meinzer St., Avenel, NJ. 07001 Continuation-impart of applications Ser. No. 470,809, July 9, 1965, Ser. No. 483,144, Aug. 27, 1965, and Ser. No. 497,851, Oct. 19, 1965. This application May 24, 1967, Ser. No. 640,866

Int. Cl. Hb 9/06 US. Cl. 219-10.61 4 Claims ABSTRACT OF THE DISCLOSURE Cross-reference to related applications This invention is a continuation-in-part of my copending applications Ser. No. 470,809, filed July 9, 1965; Ser. No. 483,144, filed Aug. 27, 1965; and Ser. No. 407,851, filed Oct. 19, 1965.

Background of invention Since an electrical conductor exposed to microwave wave irradiation within a microwave oven is impervious to microwave heating action, the general effort has been towards heating lossy workloads. In the aforementioned copending applications, there is disclosed in detail how microwave energy is converted into heat energy by controlled arcing, the microwave engendered heat being used to directly heat objects which would not become hot on exposure to microwave energy, as well as to additionally heat lossy workloads.

One object of this invention is to heat a moving conductor which is moved past a microwave generator with the generated microwave energy as the heat source. Another object of this invention is to heat treat a moving electrical conductor as wire, conduit, and the like, for subsequent processing (e.g;, drawing, jacketing with insulating material, tempering, annealing, etc.). Another object is to mechanically and continuously remove heat from a dummy load.

Some people heat treat a rapidly moving wire as it is unrolled from a large roll of wire by an intensely hot open gas flame. As in an old-fashioned wood fireplace, most of the heat goes up and out the chimney, thereby results in an extravagant waste of heat energy with the generation of harmful products of combustion and the need to dispose of such by-products. Now it is possible to rapidly heat a fast moving, good conductor by electronics. The problem is not to make the wire an integral part of the tuned circuit of a radio frequency generator where a mismatch can occur if the wire breaks or ends. The problem is to provide a high ambient temperature over a length of the moving wire to couple into this conductor a reasonable amount of heat to supplement the direct electronic heating.

Summary of the invention The problem is to heat by microwaves an electrical conductor which when passing alone thru an unmodified United States Patent 0 microwave oven would be impervious to microwave wave heating action.

The problem is solved by moving the conductor thru the high heat of a microwave kiln and making it self-heating by controlled arcing to its surface. Said another way, in this invention a moving conductor is described entering thru an opening in a wall of a microwave kiln, passing thru the region of controlled microwave arcing and out thru opposite wall of the kiln.

Brief description of the drawing In the accompanying drawing, FIGURE 1 is a composite diagram to show the salient features of this invention. The drawing depicts a cross-sectional view of a microwave kiln with wire passing through various routes therethrough; and FIGURE 2 is a detail of one opening in the wall of the microwave kiln through which the wire passes.

Description of preferred embodiments In the accompanying diagram, FIGURE 1, a copper wire to be processed unwinds from wire reel 2 and is guided on pulleys 27-31, respectively, until it is transferred to the takeup reel 4. In the cross section diagram of the microwave kiln 5, the microwave impervious (as copper screening) walls 6, bottom 7 and top 8 confine microwave energy generated by the microwave generator 9 entering working cavity 10 via waveguide 11 thru opening 12 in wall 6. Working cavity 10 is lined with microwave permeable, heat insulating material 13 as General Retractorys GR 25. The top cover 14 of microwave kiln 5 is made removable and employs conventional chokes indicated by flanges 15 and gasket 16. The weight of top cover 14, in this case, compresses flanges 15 on gasket 16 and seals microwave kiln 5 against loss of microwave energy. Top cover 14 canbe easily removed to expose working cavity 10. In working cavity 10 of microwave kiln 5 is placed conversion material 17, in the form of a plurality of particles such as ferrite or electrical carbon,

whicl1 converts microwave energy into heat energy by controlled arcing.

In the composite drawing, microwave generator 9 is turned on. The microwave energy generated travels through waveguide 11 and enters microwave kiln 5 thru microwave energy access opening 12. In working cavity -10 conversion material 17 changes the microwave energy into heat energy thru controlled arcing. At the same time, the wire 1 leaving reel 2 is directed by pulley 27 to enter microwave kiln 5 thru opening 18. Inside kiln 5, wire -1, on trip A, is heated both by the hot conversion material 17 and by microwave arcing from wire 1 to conversion material 17 until it passes out of kiln 5 via opening 19 and thru processing device 20.

Leaving processing device 20, wire 1 is redirected via pulley 28 to enter kiln 5 via opening 21 and passes thru working cavity 10 on trip B. During the first portion of trip B, wire 1 is indirectly heated by heat generated by energy conversion material 17 and for the remainder of trip B it is heated directly by conversion material 17 and microwave arcing between wire 1 and conversion material 17. Wire 1 leaves kiln 5 via opening 22 and passes thru processing device 23.

Leaving processing device 23, wire 1 is redirected via pulley 29 to enter kiln 5 via opening 24 and passes thru working cavity 10 on trip C. During all of trip C, wire 1 is heated indirectly by conversion material 17 and is unaffected by the microwave energy filling working cavity 10. Wire '1 on trip C leaves kiln 5 via opening 25 and passes thru processing deivce 26.

Leaving processing device 26, wire 1 is redirected via pulleys 30 and 31 to take up reel 4 on trip D. On trip D wire 1 is shown passing thru the waste heat rising from r 3 the kiln 5. Trip D could utilize this waste heat as it rises to dry a coating placed on wire 1 by processing device 26.

The foregoing is a composite description to illustrate various heating possibilities of a microwave kiln heating a solid, moving conductor. For the same wire speed, the wire is heated progressively less from A to D. The operator can realize a wide range of temperatures by varying the power of the microwave generator 9 and the speed of wire 1 by conventional speed change means, not shown. Heating and arcing damage to wire 1 is controlled by the size of the individual microwave arcs. The arcs are controlled by selecting different particle sizes and different types of material 17.

The kiln is made air tight to limit the amount of oxygen present or different gasses which can be introduced into working cavity 10 to chemically affect the final product. The skilled mechanic can add chemicals to the conversion material 17 to chemically react with the hot wire. The working cavity -10 can be partitioned, not shown, and wire 1 can be directed from section to section within working cavity 10 so as to heat, coat and dry said coating in sequence.

Processing devices 20, 23, and 26, as indicated, are meant to refer to old art conventional devices (e.g., wire drawing, water treating devices and the like).

Openings 18, 19, 21, 22, 24, 25 are of the same general construction, designed to contain microwave energy within kiln 5 minimize arcing between wall 6 and wire 1 and to guide wire 1 thru insulation 13. FIGURE 2 illustrates one possible construction of one of these openings where wire 1 passes thru electrical contacting fingers 32 on wall 6 and glass-ceramic guide tube 33 fixed in heat insulation 13.

If microwave kiln 5 is used as a dummy load to test microwave generator 9, the solid moving conductor wire '1 could be used to transport waste heat away from dummy load.

Wire 1 need not be solid but could be a tube. Wire 1 could be the bare outside shield on a shielded wire where it is desired to warm the shield before covering with an insulating material.

In this writing the word kiln is used to express heat confined within a good heat insulator. The actual heat of the kiln is at the operatorsoption and can be anything from a warmer to an electronic furnace.

With the foregoing and other objects in view, this in vention resides in the novel arrangement and combination of parts and in the details of construction here described and claimed, it being understood that changes in the precise embodiment of this invention here disclosed may be made within the scope of what is claimed without departing from the spirit of the invention.

I claim:

'1. Apparatus for processing a movable electrical conducting article, which comprises:

a body having a cavity therein,

heat insulating means surrounding said cavity and being permeable to microwave radiation,

a plurality of resistance particles located within said cavity,

4 means for emitting microwave energy to said particles wherein a multiude of arcs are generated thereby resulting in said microwave energy being converted into heat energy, and means for advancing an electrical conducting article through the cavity for heating the article by heat generated from said particles.

2. Apparatus according to claim -1, wherein the moving conducting article is advanced by the advancing means through the resistance particles in the cavity.

3. Apparatus for processing a movable electrical conducting article, which comprises:

a body having a cavity therein,

heat insulating means surrounding said cavity and being permeable to microwave irradiation,

a plurality of resistance particles located within said cavity,

means for emitting microwave energy to said particles wherein a multitude of arcs are generated thereby resulting in said microwave energy being converted into heat energy, and

means for advancing an electrical conducting article through the cavity for heating the article by heat generated from said particles, said advancing means further providing for a return of said moving conducting article through the cavity wherein the article is heated both by the heat directly generated from the particles and by microwave arcing between the particles and conducting article.

4. Apparatus according to claim 1, wherein the advancing means further provides for a return of said moving conducting article through the cavity wherein the conducting article is heated by the heat generated from the particles;

References Cited UNITED STATES PATENTS OTHER REFERENCES Copson: Microwave Heating, pages 283-285, 1962. Homann, Gerarnn Application 1,120,619, printed Dec. 28, 1961 (K1. 21h 36) 2 pages spec., 2 pages drawing.

JOSEPH V. TRUHUE, Primary Examiner.

L. H. B'ENDER, Assistant Examiner.

US. Cl. XJR. 219-1055 

